New Targets for Reproductive Control of Mosquito Vectors Project summary/abstract In this project, we will investigate the male seminal fluid proteins (SFPs) of a major disease vector of dengue, Zika and chikungunya viruses: the yellow fever mosquito (Aedes aegypti). Insect SFPs trigger major changes in female physiology, conducive to high fertility (e.g. increased egg production), regulating re-mating and, in mosquitoes, potentially regulating blood feeding physiology. Dengue is an old scourge, but new pathogens such as chikungunya and Zika that cycled silently in their sylvatic backdrop have surged forward and crossed hemispheres with a vengeance. There is an immediate need to develop novel and effective vector control strategies for these vectors. In the present funding period, we identified Aedes SFPs and obtained bioactive fractions and identified components. We developed assays for testing the effects of the components, and have been successful in using CRISPR-based genome editing to mutate our first candidates for bioactive SFPs. We also determined the effect of mating on SFP stores (and production) in males, and on the transcriptome of the mated female. In this renewal application, for continued support for this project, we propose three specific aims to (1) identify and functionally characterize bioactive SFPs in vivo in Ae. aegypti, (2) determine female molecular responses to SFPs in general and physiological and molecular responses to specific, bioactive, SFPs and (3) understand the phenotypic and genetic variation of SFPs and their responsive targets in field relevant populations of this mosquito vector. Our goal is to identify SFPs, and SFP targets, that could be manipulated as a novel means of reproductive control, or to modify the blood feeding physiology of these insects that transmit deadly pathogens, with the long-term goal to reduce or eliminate virus transmission to people.